Ecdysterone: Does This Plant Steroid Actually Build Muscle?

Ecdysterone has earned a reputation as nature's anabolic steroid, and the human data is more interesting than most supplement hype.

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By the Ration Editorial Team · Reviewed against primary research · Updated July 13, 2026

Ecdysterone, also called 20-hydroxyecdysone, is a steroid hormone made by plants and insects.

In insects it drives molting and metamorphosis. In plants like spinach and quinoa, it seems to work as a natural pesticide, deterring insects that eat the leaves.

Despite its steroid structure, ecdysterone is not a testosterone derivative. It has drawn attention as a legal, over the counter alternative to anabolic steroids, sometimes nicknamed 'nature's anabolic steroid' in bodybuilding circles.

The leading theory is that ecdysterone binds to estrogen receptor beta, a receptor found in skeletal muscle tissue.^[6]

This is a key distinction from anabolic androgenic steroids, which act on androgen receptors. Activating estrogen receptor beta appears to trigger pathways that increase protein synthesis in muscle cells.^[8]

Animal studies support this mechanism. Mice given continuous infusions of 20-hydroxyecdysone showed measurable increases in triceps muscle mass.^[7]

A related compound called poststerone, which the body produces as ecdysterone breaks down, also increased muscle fiber size in lab studies, suggesting some of the effect may come from downstream metabolites rather than ecdysterone alone.^[3]

Human evidence is still limited to a handful of trials, but the direction of the findings has been consistent enough that our database grades both lean body mass and strength outcomes as A-level, based on 6 sources each.

• ↑Lean Body MassAHuman trials

  Research may raise Lean Body Mass · strong agreement · 6 studies

  View 5 studies on PubMed

  • How reliable is the labeling of a commercial phytosteroid product? A 12-week randomized double-blind training study (2025)
  • Ecdysteroids as non-conventional anabolic agent: performance enhancement by ecdysterone supplementation in humans (2019)
  • A Phase 1 study for safety and pharmacokinetics of BIO101 (20-hydroxyecdysone) in healthy young and older adults (2023)
  • Ecdysteroids: A novel class of anabolic agents? (2015)
  • Poststerone increases muscle fibre size partly similar to its metabolically parent compound, 20-hydroxyecdysone (2019)
• ↑StrengthAHuman trials

  Research may raise Strength · strong agreement · 6 studies

  View 5 studies on PubMed

  • How reliable is the labeling of a commercial phytosteroid product? A 12-week randomized double-blind training study (2025)
  • Ecdysteroids as non-conventional anabolic agent: performance enhancement by ecdysterone supplementation in humans (2019)
  • β-Ecdysone Augments Peak Bone Mass in Mice of Both Sexes (2015)
  • Phytoecdysteroids increase protein synthesis in skeletal muscle cells (2008)
  • Effects of methoxyisoflavone, ecdysterone, and sulfo-polysaccharide supplementation on training adaptations in resistance-trained males (2006)

The trial most often cited is a randomized study in resistance-trained men, where ecdysterone supplementation was associated with greater increases in lean body mass and one-rep max bench press strength compared with placebo, alongside signs of increased anabolic signaling in muscle tissue.^[4]

An older resistance-training study testing ecdysterone alongside methoxyisoflavone and a sulfo-polysaccharide found some support for training adaptations, though the multi-ingredient design makes it hard to isolate ecdysterone's individual contribution.^[9]

A review of herbal ergogenic aids for exercise performance covered ecdysterone among other botanicals and found the evidence at the time promising but preliminary.^[10]

More recent work has tried to tighten the picture. A 12-week randomized, double-blind training study specifically tested a commercial phytosteroid product, and part of its contribution was flagging that label claims on ecdysterone supplements do not always match what is actually in the bottle.^[1]

Animal research adds a broader anabolic picture beyond muscle. In mice, 20-hydroxyecdysone increased peak bone mass in both males and females, hinting at effects that might extend past skeletal muscle.^[5]

Taken together, the human trials are small, short, and not yet numerous enough to call this settled. But the consistency of the direction, more lean mass and more strength, is why the evidence grade sits as high as it does for a compound this under-studied.^[4][9]

Ecdysterone occurs naturally in several common foods, though at fairly low concentrations compared to concentrated supplements.

• Spinach
• Quinoa
• Yam
• Certain insects, including some beetle species
• Achyranthes and Cyanotis plant extracts, common bases for commercial supplements

Most people trying ecdysterone for performance use a standalone capsule or powder supplement derived from plant extracts rather than eating spinach in quantity, since dietary intake alone is unlikely to reach the doses used in trials.

Doses in human research have varied. Some trials used doses in the range of a few hundred milligrams per day, split across the day, over 8 to 12 week training blocks.^[4][9]

There is no established consensus dose for ecdysterone, and no regulatory body has set an official recommended intake.

Product quality is a genuine issue. A 2025 randomized trial specifically testing a commercial phytosteroid supplement found discrepancies between what was on the label and what the product actually contained, echoing long standing concerns in the sports supplement industry.^[1]

Anyone considering an ecdysterone supplement may want to look for third party testing given this labeling inconsistency.

A Phase 1 trial evaluating the safety and pharmacokinetics of a purified 20-hydroxyecdysone compound, called BIO101, in both healthy young and older adults reported that the compound was generally well tolerated across the doses tested.^[2]

Because ecdysterone appears to act through estrogen receptor beta rather than androgen receptors, it is theorized to avoid many of the hormonal side effects associated with anabolic androgenic steroids, such as suppression of natural testosterone production.^[6]

That said, long term safety data in humans is thin. Most trials run 8 to 12 weeks, and there is little information on effects with years of continuous use.

Ecdysterone is banned by the World Anti-Doping Agency in competitive sport, so athletes subject to drug testing should be aware of this before use.

• Resistance-trained individuals looking for a legal alternative to anabolic steroids, though evidence is still preliminary
• People already following a structured strength training program, since the trials showing benefit paired supplementation with resistance training, not supplementation alone
• Researchers and clinicians interested in estrogen receptor beta as a muscle-building target
• Older adults, based on early safety data, though efficacy data in this group specifically is limited^[2]

Ecdysterone is unlikely to do much for someone not also lifting weights, since every positive human trial paired it with a structured resistance training program.

Ecdysterone stands out among plant compounds marketed for muscle building because it actually has human randomized trial data behind it, not just animal studies and tradition.^[4][9]

The evidence base is still small, and product quality control is inconsistent, so results in the real world may vary more than the tightly controlled trial data suggests.^[1]

For now, ecdysterone looks like one of the more promising natural compounds in the muscle-building category, without yet reaching the level of certainty that decades of research have given creatine or protein.